Detection of light from cells, cell lysates and animals carrying a fluorescent probe is a powerful tool in diagnostics, drug discovery and medicine that allows for the identification of disease pathways, determination of mechanisms of action, evaluation of efficacy of drug compounds, and monitoring lead candidates' effects on disease progression (e.g., cancer, bacterial infection, etc.), trauma, cell death and the like in living animals. See, e.g., U.S. Pat. Nos. 7,449,615; 7,255,851; 7,198,774; 6,939,533; 6,923,951; 6,916,462; 6,908,605; 6,890,515; 6,649,143; 6,217,847; and 5,650,135.
Fluorescent probes are described in U.S. Patent Nos. 20050214221 and 20050171434. In addition, Jin et al. (2007) Molecular Cancer 6:43-55 describes in vivo imaging of RGD mediated internalization using the multivalent quenched RAFT-c(-RGDfK-)(4)-Cy5-SS-Q probe. U.S. Patent Publication No. 20080171351 describes optical imaging of bacterial infections using probes that target molecules (e.g., anionic phospholipids) present in the bacterial envelope. See, also, White et al. (2010) Bioconjugate Chem. 21:1297-1304 and Leevy et al. (2008) Bioconjugate Chem. 19:686-692.
However, despite the wide-spread use of imaging techniques, there remains a need a need for additional multivalent fluorescent probes.